-Advertisement-
  About AE   About NHM   Contact Us   Terms of Use   Copyright Info   Privacy Policy   Advertising Policies   Site Map
Ads on AE Graphics Gallery
Custom Search of AE Site
spacer spacer

Photosynthesis and Respiration

   Copyright 2004 by Alberts, Bray, Johnson, Lewis, Raff, Roberts, Walter.
Garland Publishing: Taylor Francis Group.

Photosynthesis and Respiration


Photosynthesis uses the energy of sunlight to produce sugars and other organic molecules. These molecules in turn serve as food for other organisms. Many of these organisms carry out respiration, a process that uses O2 to form CO2 from the same carbon atoms that had been taken up as CO2 and converted into sugars by photosynthesis. In the process, the organisms that respire obtain the chemical bond energy that they need to survive. The first cells on the earth are thought to have been capable of neither photosynthesis nor respiration (see Chapter 14). However, photosynthesis must have preceded respiration on the earth, since there is strong evidence that billions of years of photosynthesis were required before O2 had been released in sufficient quantity to create an atmosphere rich in this gas to support respiration. (The earth's atmosphere presently contains 20% O2.)  Fair Use and Copyright info

 
Graphics Gallery Visual Library Resource Center Forward to a Friend

 
Custom Search on the AE Site

 

-Advertisement-